| Cooperation-Induced Topological Complexity: A Promising Road to Fault Tolerance and Hebbian Learning |
16 Mar 2012 |
8 pages |
| Authors:
Malgorzata Turalska; Elvis Geneston; Bruce J West; Paolo Allegrini; Paolo Grigolini; ARMY RESEARCH LAB RESEARCH TRIANGLE PARK NC ARMY RESEARCH OFFICE/INFORMATION SCIENCES DIRECTORATE
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 | According to an increasing number of researchers intelligence emerges from criticality as a consequence of locality breakdown and long-range correlation, well known properties of phase transition processes.We study a model of interacting units, as an idealization of real cooperative systems such as the brain or a flock of birds, for the purpose of discussing the emergence of long-range correlation from the coupling of any unit with its nearest neighbors. We ... |
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| A Simple Algorithm for Obtaining Nearly Optimal Quadrature Rules for NURBS-based Isogeometric Analysis |
05 Jan 2012 |
32 pages |
| Authors:
F Auricchio; F Calabro; T J Hughes; A Reali; G Sangalli; TEXAS UNIV AT AUSTIN INST FOR COMPUTATIONAL ENGINEERING AND SCIENCES
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| We develop new quadrature rules for Isogeometric Analysis based on the solution of a local nonlinear problem. A simple and robust algorithm is developed to determine the rules which are exact for important B-Spline spaces of uniform and geometrically stretched knot spacings. We consider both periodic and open knot vector configurations and illustrate the efficiency of the rules on selected boundary value problems. We find that the rules are almost ... |
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| Testing Properties of Boolean Functions |
Jan 2012 |
165 pages |
| Authors:
Eric Blais; CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE
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| Given oracle access to some boolean function f, how many queries do we need to test whether f is linear? Or monotone? Or whether its output is completely determined by a small number of the input variables? This thesis studies these and related questions in the framework of property testing introduced by Rubinfeld and Sudan ('96). The results of this thesis are grouped into three main lines of research. I. ... |
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| Analytical Solution in Curvilinear Coordinates for the Trajectory of a Projectile Subject to Aerodynamic Drag |
Dec 2011 |
38 pages |
| Authors:
Steven B Segletes; William P Walters; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| An analytical study was conducted to determine the general trajectory of a projectile subject to aerodynamic drag in a gravitational field. A solution was obtained to the governing equations using curvilinear coordinates. The general solution analytically provides the pathlength of the projectile in terms of the current trajectory angle. Noticeably absent from the solution, however, are several desirable quantities. For instance, there is no ability to analytically express the trajectory ... |
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| Topological Patterns for Scalable Representation and Analysis of Dataflow Graphs |
Nov 2011 |
24 pages |
| Authors:
Nimish Sane; Hojin Kee; Gunasekaran Seetharaman; Shuvra S Bhattacharyya; MARYLAND UNIV COLLEGE PARK INST FOR ADVANCED COMPUTER STUDIES
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| Tools for designing signal processing systems with their semantic foundation in dataflow modeling often use high-level graphical user interfaces (GUIs) or text based languages that allow specifying applications as directed graphs. Such graphical representations serve as an initial reference point for further analysis and optimizations that lead to platform-specific implementations. For large-scale applications the underlying graphs often consist of smaller substructures that repeat multiple times. To enable more concise representation ... |
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| Multi-camera Human Tracking via Clustering |
Nov 2011 |
19 pages |
| Authors:
Dmitri Kamenetsky; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION EDINBURGH (AUSTRALIA)
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| We describe an efficient method for tracking humans in a multi-camera network. Based on online clustering, the proposed method groups single-camera tracks into mutually exclusive subsets corresponding to individuals. Experiments indicate that the algorithm is capable of achieving strong tracking accuracy on simulated data. |
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| Summer Co-op Outbrief: Themis Cavitating Venturi Resonance Study |
27 Oct 2011 |
41 pages |
| Authors:
Phuoc H Tran; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| This presentation examines the propagation and properties of acoustic disturbances caused by cavitating venture at different operating regimes. Issues of interest are effects on cold flow and water visualization jets (injectors) and the Big Picture: LRE systems. There is a lack of literature pertaining to unsteady characteristics. Theory is explored, along with test details for design space, test facility, test apparatus, and preliminary results. |
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| Next-Generation Parametric Reduced-Order Models |
24 Oct 2011 |
57 pages |
| Authors:
Sung-Kwon Hong; Bogdan I Epureanu; Matthew P Castanier; ARMY TANK AUTOMOTIVE RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
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| Novel parametric reduced-order models are proposed for fast reanalysis to predict the dynamic response of complex structures, which suffered thickness variations caused by design changes or damage in one or more substructures. Parametric reduced-order models developed previously have two important challenges to overcome to improve accuracy and performance: (a) the transformation matrix is not mathematically stable, (b) the Taylor series parameterization techniques do not capture thickness variations of the structure ... |
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| Proper Orthogonal Decomposition Analysis of Shear-Coaxial Injector Flows With and Without Transverse Acoustic Forcing |
13 Oct 2011 |
18 pages |
| Authors:
Sophonias Teshome; Ivett Leyva; Douglas Talley; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIR/SPACE AND MISSILE PROPULSION DIV/AEROPHYSICS BRANCH
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| This experimental study investigated the response of dynamic flow structures of cryogenic coaxial nitrogen jets to pressure perturbations due to transverse acoustic forcing at a pressure antinode (PAN). The role of injector exit geometry on the flow response was examined using two shear coaxial injectors with different outer-to-inner jet area ratios. Flow conditions spanning subcritical (reduced pressure of 0.44) to supercritical (reduced pressure of 1.05) chamber pressures, varying outer-to-inner jet ... |
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| Data-Driven Boundary Correction and Optimization of a Nearshore Wave and Hydrodynamic Model to Enable Rapid Environmental Assessment |
30 Sep 2011 |
5 pages |
| Authors:
James M Kaihatu; TEXAS A AND M UNIV COLLEGE STATION DEPT OF CIVIL ENGINEERING
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| The present project is part of a comprehensive effort by the PI, his students, and collaborators at the Naval Research Laboratory to increase the robustness and viability of the Delft3D model suite as an operational forecasting tool, and aid its continued transition to Navy forecasting centers. Prior projects have focused on determining the model s response to characteristics and sample sizes of bathymetric information. The present project focuses on determining ... |
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| Phase History Decomposition for efficient Scatterer Classification in SAR Imagery |
15 Sep 2011 |
194 pages |
| Authors:
Dane F Fuller; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| A new theory and algorithm for scatterer classification in SAR imagery is presented. The automated classification process is operationally efficient compared to existing image segmentation methods requiring human supervision. The algorithm reconstructs coarse resolution subimages from subdomains of the SAR phase history. It analyzes local peaks in the subimages to determine locations and geometric shapes of scatterers in the scene. Scatterer locations are indicated by the presence of a stable ... |
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| Analysis of Transient Electromagnetic Scattering from an Overfilled Cavity Embedded in an Impedance Ground Plane |
Sep 2011 |
138 pages |
| Authors:
Robert S Callihan; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| We consider the transient, or time-domain, scattering problem of a two-dimensional overfilled cavity embedded in an impedance ground plane. This problem is a significant advancement from previous work where more simplified boundary conditions were used, which can limit the number of applications. This research supports a wide range of military applications such as the study of cavity-like structures on aircraft and vehicles. More importantly, this research helps detect the biggest ... |
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| Isogeometric Analysis for Topology Optimization with a Phase Field Model |
Sep 2011 |
64 pages |
| Authors:
L Dede; M J Borden; T J Hughes; TEXAS UNIV AT AUSTIN INST FOR COMPUTATIONAL ENGINEERING AND SCIENCES
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| We consider a phase field model for the formulation and solution of topology optimization problems in the minimum compliance case. In this model, the optimal topology is obtained as the steady state of the phase transition described by the generalized Cahn-Hilliard equation which naturally embeds the volume constraint on the amount of material available for distribution in the design domain. We reformulate the model as a coupled system and we ... |
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| Green's Symmetries In Finite Digraphs |
15 AUG 2011 |
11 pages |
| Authors:
Allen D. Parks; NAVAL SURFACE WARFARE CENTER DAHLGREN VA ELECTROMAGNETIC AND SENSOR SYSTEMS DIV
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| The semigroup D(sub V) of digraphs on a set V of n labeled vertices is defined. It is shown that D(sub V) is faithfully represented by the semigroup B(sub n) of n x n Boolean matrices and that the Green's L, R, H, and D equivalence classifications of digraphs in D(sub V) follow directly from the Green's classifications already established for Bn. The new results found from this are: (i) ... |
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| Fiedler Trees for Multiscale Surface Analysis |
Aug 2011 |
13 pages |
| Authors:
Matt Berger; Luis G Nonato; Valerio Pascucci; Claudio T Silva; AIR FORCE RESEARCH LAB ROME NY INFORMATION DIRECTORATE
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| In this work we introduce a new hierarchical surface decomposition method for multiscale analysis of surface meshes. In contrast to other multiresolution methods, our approach relies on spectral properties of the surface to build a binary hierarchical decomposition. Namely, we utilize the first nontrivial eigenfunction of the Laplace-Beltrami operator to recursively decompose the surface. For this reason we coin our surface decomposition the Fielder tree. Using the Fiedler tree ensures ... |
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| Policy-Based Design and Verification for Mission Assurance |
Aug 2011 |
15 pages |
| Authors:
Shiu-Kai Chin; Sarah Muccio; Susan Older; Thomas N Vestal; SYRACUSE UNIV NY DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
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| Intelligent systems often operate in a blend of cyberspace and physical space. Cyberspace operations planning, actions, and effects in realms where signals affect intelligent systems - often occur in milliseconds without human intervention. Decisions and actions in cyberspace can affect physical space, particularly in SCADA - supervisory control and data acquisition systems. For critical military missions, intelligent and autonomous systems must adhere to commander intent and operate in ways that ... |
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| Tailored Granular Activated Carbon Treatment of Perchlorate in Drinking Water. ESTCP Cost and Performance Report |
Aug 2011 |
50 pages |
| Authors:
Trent Henderson; Fred Cannon; ARCADIS US DURHAM NC
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| Perchlorate is a concern in drinking water because of its high solubility and mobility, its effects on thyroid hormone production, and treatment cost. Although perchlorate removal technologies suitable for wellhead application exist, there is a need to develop additional, economical perchlorate removal technologies. In addition, conventional wellhead technologies are specific for perchlorate only and are unable to effectively treat volatile organic compounds (VOCs) that are often co-contaminants. This project demonstrated ... |
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| Existence, Uniqueness and Stability of Solutions of Generalized Tikhonov-Phillips Functionals |
Aug 2011 |
26 pages |
| Authors:
G L Mazzieri; R D Spies; K G Temperini; MINNESOTA UNIV MINNEAPOLIS INST FOR MATHEMATICS AND ITS APPLICATIONS
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| The Tikhonov-Phillips method is widely used for regularizing ill-posed inverse problems mainly due to the simplicity of its formulation as an optimization problem. The use of different penalizers in the functionals associated to the corresponding optimization problems has originated a variety other methods which can be considered as variants of the traditional Tikhonov-Phillips method of order zero. Such is the case for instance of the Tikhonov-Phillips method of order one, ... |
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| Efficient Implementation of High Order Inverse Lax-Wendroff Boundary Treatment for Conservation Laws |
15 Jul 2011 |
36 pages |
| Authors:
Sirui Tan; Cheng Wang; Chi-Wang Shu; Jianguo Ning; BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS
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| In [18], two of the authors developed a high order accurate numerical boundary condition procedure for hyperbolic conservation laws on a Cartesian mesh, which allows the computation using high order finite difference schemes on Cartesian meshes to solve problems in arbitrary physical domains whose boundaries do not coincide with grid lines. This procedure is based on the so-called inverse Lax-Wendroff (ILW) procedure for inflow boundary conditions and high order extrapolation ... |
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| High Order Finite Difference Methods with Subcell Resolution for Advection Equations with Stiff Source Terms |
16 Jun 2011 |
43 pages |
| Authors:
Wei Wang; Chi-Wang Shu; H C Yee; Bjoern Sjoegreen; BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS
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| A new high order finite-difference method utilizing the idea of Harten ENO subcell resolution method is proposed for chemical reactive flows and combustion. In reaction problems, when the reaction time scale is very small, e.g., orders of magnitude smaller than the fluid dynamics time scales, the governing equations will become very stiff. Wrong propagation speed of discontinuity may occur due to the underresolved numerical solution in both space and time. ... |
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| Gradients and Non-Adiabatic Derivative Coupling Terms for Spin-Orbit Wavefunctions |
JUN 2011 |
227 pages |
| Authors:
Lachlan T. Belcher; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
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| Analytic gradients of electronic eigenvalues require one calculation per nuclear geometry, compared to 3n calculations for finite difference methods, where n is the number of nuclei. Analytic non-adiabatic derivative coupling terms, which are calculated in a similar fashion, are used to remove non-diagonal contributions to the kinetic energy operator, leading to more accurate nuclear dynamics calculations than those that employ the Born-Oppenheimer approximation and assume off-diagonal contributions are zero. The ... |
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| A Topological Model for C2 Organizations |
JUN 2011 |
54 pages |
| Authors:
Andre L. Uruguay; Carlos H. Ribeiro; INSTITUTE FOR ADVANCED STUDIES SAO JOSE DOS CAMPOS (BRAZIL)
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| One essential function in Command is to determine roles, responsibilities and relationships, in order to enable, encourage and constrain certain behaviors. In the context of the complex endeavors expected to happen in the near future, this means to establish a collection of organizations that are fit for the missions. On the other hand, in recent years the mathematical field of Topology has been applied to solve several problems of multiagent ... |
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| Coherent Noise Rejection in a Three-Phase Power Inverter |
JUN 2011 |
55 pages |
| Authors:
Daniel G. Wheaton; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| In this thesis, we discuss the design of a controller to reject the effects of high order harmonics in a three-phase power inverter. Specifically, coherent noise in the fifth harmonic is considered, as it seems to be dominant in most applications. The controller used in this power inverter operates in a reference frame synchronous with the 60 Hz line voltage. This transformation effectively changes the desired 60 Hz sine wave ... |
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| Analysis of the Hessian for Inverse Scattering Problems. Part 1: Inverse Shape Scattering of Acoustic Waves |
Jun 2011 |
40 pages |
| Authors:
Tan Bui-Thanh; Omar Ghattas; TEXAS UNIV AT AUSTIN INST FOR COMPUTATIONAL ENGINEERING AND SCIENCES
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| We derive expressions for the shape Hessian operator of the data misfit functional corresponding to the inverse problem of inferring the shape of a scatterer from reflected acoustic waves, using a Banach space setting and the Lagrangian approach. The shape Hessian is then analyzed in both Hoelder and Sobolev spaces. Using an integral equation approach and compact embeddings in Hoelder and Sobolev spaces, we show that the shape Hessian can ... |
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| Propagation of 3-D Beams Using a Finite-Difference Algorithm: Practical Considerations |
22 May 2011 |
12 pages |
| Authors:
Alan H Paxton; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
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| We discuss practical aspects of the use of the finite-difference, alternating-direction implicit (ADI), numerical solution of the paraxial wave equation, for the free-space propagation of light beams. Results of calculations solving the finite-difference equations are compared with fresnal-integral solutions. Calculations are for round beams, but the field is represented in cartesian coordinates. Modes for empty unstable resonators are also obtained using the finite-difference algorithm and are compared with fresnal-difference. |
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| Comparison of Optimal Design Methods in Inverse Problems |
11 May 2011 |
52 pages |
| Authors:
H T Banks; Kathleen Holm; Franz Kappel; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
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| Typical optimal design methods for inverse or parameter estimation problems are designed to choose optimal sampling distributions through minimization of a specific cost function related to the resulting error in parameter estimates. It is hoped that the inverse problem will produce parameter estimates with increased accuracy using data from the optimal sampling distribution. We present a new Prohorov metric based theoretical framework that permits one to treat succinctly and rigorously ... |
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| Subspace Arrangement Codes and Cryptosystems |
09 May 2011 |
51 pages |
| Authors:
James A Berg; NAVAL ACADEMY ANNAPOLIS MD
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| Errors often occur in transferring electronic data, ranging from sensitive government information to everyday bar codes. Encoding information with an error-correcting code can alleviate the problem of corrupt or lost data. In order to not overburden computing systems, an efficient code must be used that will quickly encode and decode data while detecting and correcting a large number of errors. The goal of this project is to construct and develop ... |
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| Standardizing U.S. Military Foreign Disaster Relief with the U.N. |
04 MAY 2011 |
1 pages |
| Authors:
Brad A. Bane; NAVAL WAR COLL NEWPORT RI JOINT MILITARY OPERATIONS DEPT
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| The lack of standardized procedures among the U.S. military and other disaster relief agencies results in inefficiencies during foreign disaster relief operations. These inefficiencies normally include breakdowns in information sharing, duplication of effort and delays in providing effective relief across the full spectrum of response forces. The United Nations has recently developed a "Cluster Approach" to international disaster relief which has gained notoriety as an effective method to mitigate many ... |
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| An Inverse Problem with Single Measurement Generated by a Plane Wave |
03 MAY 2011 |
15 pages |
| Authors:
Michael V. Klibanov; NORTH CAROLINA UNIV AT CHARLOTTE DEPT OF MATHEMATICS AND STATISTICS
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| Global uniqueness of inverse problem for a hyperbolic PDE with the unknown potential and a single incident plane wave is a well known long standing open question. This question is addressed for the case when derivatives with respect to variables orthogonal to this plane wave are expressed via finite differences. |
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| Free-Wave Propagation Relationships of Second-Order and Fourth-Order Periodic Systems |
04 Apr 2011 |
17 pages |
| Authors:
Andrew J Hull; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI AUTONOMOUS AND DEFENSIVE SYSTEMS DEPT
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| This report develops an analytical expression for the determinant of two diagonally-indexed, full matrices when they are zero. These matrices originate from second- and fourth-order periodic system theory. The partial differential equations of these systems are solved using a series solution and are converted into closed-form analytical expressions The denominators of these expressions are zero when free-wave propagation is present, and these denominators are equated to the determinants of the ... |
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| Stochastic Differential Dynamic Logic for Stochastic Hybrid Programs |
Apr 2011 |
27 pages |
| Authors:
Andre Platzer; CARNEGIE-MELLON UNIV PITTSBURGH PA DEPT OF COMPUTER SCIENCE
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| Logic is a powerful tool for analyzing and verifying systems, including programs, discrete systems real-time systems, hybrid systems, and distributed systems. Some applications also have a stochastic behavior, however, either because of fundamental properties of nature, uncertain environments or simplifications to overcome complexity. Discrete probabilistic systems have been studied using logic. But logic has been chronically underdeveloped in the context of stochastic hybrid systems, i.e., systems with interacting discrete, continuous, ... |
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| Inverse Problems for Nonlinear Delay Systems |
15 Mar 2011 |
32 pages |
| Authors:
H T Banks; Keri Rehm; Karyn Sutton; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
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| We consider inverse or parameter estimation problems for general nonlinear nonautonomous dynamical systems with delays. The parameters may be from a Euclidean set as usual, may be time dependent coefficients or may be probability distributions across a population as arise in aggregate data problems. Theoretical convergence results for finite dimensional approximations to the systems are given. Several examples are used to illustrate the ideas and computational results that demonstrate efficacy ... |
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| Green Hypergolic Bipropellants: H202/Hydrogen-Rich Ionic Liquids |
04 MAR 2011 |
20 pages |
| Authors:
Stefan Schneider; Tom Hawkins; Yonis Ahmed; Michael Rosander; Jeff Mills; Leslie Hudgens; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| The low vapor toxicity of ionic liquids (ILs) make them attractive replacements for hydrazine in rocket applications. However, ILs will fail to fulfill their revolutionary promise unless toxic oxidizers like HNO3 or N2O4 can be replaced with safer alternatives. By their very nature all rocket oxidizers are hazardous and so reducing those hazards, even though the resulting materials might not be completely harmless, is at the heart of green initiatives ... |
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| Follower-Force Experiments with Geometric Non-linear Coupling for Analytical Validation |
Mar 2011 |
80 pages |
| Authors:
Tae H Kim; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| This study was a follow-up of a previous study where static deflection data of a joined-wing test article was collected from a series of experiments using a laser scanner and a laser tracker while the test articles were subjected to follower-forces. One of the goals of this study was to collect accurate experimental data which could be used to validate analytical methods, such as geometrically exact beam theory, which are ... |
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| Traveling Along a Zipline |
Mar 2011 |
5 pages |
| Authors:
Carl E Mungan; Trevor C Lipscombe; NAVAL ACADEMY ANNAPOLIS MD DEPT OF PHYSICS
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| The trajectory of a rider slowly traversing a zipline of fixed length and endpoints is computed, as a one-dimensional illustration of the curving of spacetime by a mass. As the rider?s weight increases from 0 to ∞, the trajectories uniformly interpolate between a catenary and an ellipse. These results are obtained by balancing forces in the horizontal and vertical directions, so that the treatment is accessible to undergraduate physics majors ... |
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| Function Extraction (FX) Research for Computation of Software Behavior: 2010 Development and Application of Semantic Reduction Theorems for Behavior Analysis |
Feb 2011 |
35 pages |
| Authors:
Richard Linger; Tim Daly; Mark Pleszkoch; CARNEGIE-MELLON UNIV PITTSBURGH PA SOFTWARE ENGINEERING INST
|
| For several years, the Software Engineering Institute (SEI) at Carnegie Mellon University has been engaged in a project to compute the behavior of software with mathematical precision to the maximum extent possible. Air Force Office of Scientific Research (AFOSR) sponsorship has played a key role in this effort. The general thrust of the research for AFOSR has been in technology for the following: (1) overcoming difficult aspects of behavior computation, ... |
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| Third-Order Family of Methods in Banach Spaces |
24 Jan 2011 |
15 pages |
| Authors:
Changbum Chun; Pantelimon Stanica; Beny Neta; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF APPLIED MATHEMATICS
|
| Recently, Parida and Gupta (J. Comp. Appl. Math. v206 (2007) p873-877) used Rall's recurrence relations approach (from 1961) to approximate roots of nonlinear equations by developing several methods, the latest of which is free of second derivatives and is of the third order. In this paper, the authors use an idea from Kou and Li (Appl. Math. Comp. v187 (2007), p1027-1032) and modify the approach of Parida and Gupta to ... |
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| Traditional Statistical Measures Comparing Weather Research and Forecast Model Output to Observations Centered Over Utah |
Jan 2011 |
336 pages |
| Authors:
John Raby; Jeff Passner; Robert Brown; Yasmina Raby; ARMY RESEARCH LAB WHITE SANDS MISSILE RANGE NM COMPUTATIONAL AND INFORMATION SCIENCE DIRECTORATE
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| The Model Assessment Project automated legacy scripts produce model validation statistics using the National Center for Atmospheric Research (NCAR) Model Evaluation Tools (MET) software. The project also accessed the Meteorological Assimilation Data Ingest System (MADIS) mesonet observation data to augment the legacy National Centers for Environmental Prediction (NCEP) PrepBUFR METAR observational data to provide a twenty-fold increase in the number of observations to compare with model forecasts. MET Point-Stat was ... |
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| Observability of the Doi Orientation Tensor Model |
Jan 2011 |
15 pages |
| Authors:
Hong Zhou; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF APPLIED MATHEMATICS
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| We apply the observability rank condition to the two-dimensional Doi orientation tensor model to investigate the observability of liquid crystalline polymers under imposed shear or extensional flows. Here the observability means the ability of determining the orientation tensor from the time history of the observations of the birefringence. The Doi model under shear or extensional flow is observable almost everywhere. In other words, all components of the orientation tensor can ... |
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| Beyond Graphs: Capturing Groups in Networks |
Jan 2011 |
7 pages |
| Authors:
R Ramanathan; A Bar-Noy; P Basu; M Johnson; W Ren; A Swami; Q Zhao; ARMY RESEARCH LAB ADELPHI MD
|
| Currently, the de facto representational choice for networks is graphs. A graph captures pairwise relationships (edges) between entities (vertices) in a network. Network science however, is replete with group relationships that are more than the sum of the pairwise relationships. For example, collaborative teams, wireless broadcast, insurgent cells, coalitions all contain unique group dynamics that need to be captured in their respective networks. We propose the use of the (abstract) ... |
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| The Independence Number for the Generalized Petersen Graphs |
Jan 2011 |
14 pages |
| Authors:
Joseph Fox; Ralucca Gera; Pantelimon Stanica; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF APPLIED MATHEMATICS
|
| Given a graph G, an independent set I(G) is a subset of the vertices of G such that no two vertices in I(G) are adjacent. The independence number alpha(G) is the order of the largest set of independent vertices. In this paper, we study the independence number for the Generalized Petersen graphs, finding both sharp bounds and exact results for subclasses of the Generalized Petersen graphs. |
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| On a Combinatorial Conjecture |
Jan 2011 |
14 pages |
| Authors:
Thomas W Cusick; Yuan Li; Pantelimon Stanica; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF APPLIED MATHEMATICS
|
| Recently, Tu and Deng proposed a combinatorial conjecture about binary strings and, on the assumption that the conjecture is correct, they obtained two classes of Boolean functions that are both algebraic immunity optimal, the first class of which are also bent functions. The second class gives balanced functions, which have optimal algebraic degree and the best nonlinearity known until now. In this paper, using three different approaches, we prove that ... |
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| Diffuse Interface Models on Graphs for Classification of High Dimensional Data |
Jan 2011 |
30 pages |
| Authors:
Andrea L Bertozzi; Arjuna Flenner; CALIFORNIA UNIV LOS ANGELES DEPT OF MATHEMATICS
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| There are currently several communities working on algorithms for classi cation of high dimensional data. This work develops a class of variational algorithms that combine recent ideas from spectral methods on graphs with nonlinear edge/region detection methods traditionally used in in the PDE-based imaging community. The algorithms are based on the Ginzburg-Landau functional which has classical PDE connections to total variation minimization. Convex-splitting algorithms allow us to quickly nd minimizers ... |
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| Convex Graph Invariants |
02 Dec 2010 |
31 pages |
| Authors:
Venkat Chandrasekaran; Pablo A Parrilo; Alan S Willsky; MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INFORMATION AND DECISION SYSTEMS
|
| The structural properties of graphs are usually characterized in terms of invariants, which are functions of graphs that do not depend on the labeling of the nodes. In this paper we study convex graph invariants, which are graph invariants that are convex functions of the adjacency matrix of a graph. Some examples include functions of a graph such as the maximum degree the MAXCUT value (and its semidefinite relaxation), and ... |
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| The Convex Geometry of Linear Inverse Problems |
02 Dec 2010 |
39 pages |
| Authors:
Venkat Chandrasekaran; Benjamin Recht; Pablo A Parrilo; Alan S Willsky; MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INFORMATION AND DECISION SYSTEMS
|
| In applications throughout science and engineering one is often faced with the challenge of solving an ill-posed inverse problem, where the number of available measurements is smaller than the dimension of the model to be estimated. However in many practical situations of interest, models are constrained structurally so that they only have a few degrees of freedom relative to their ambient dimension. This paper provides a general framework to convert ... |
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| Scattering Matrix Elements for the Nonadiabatic Collision |
Dec 2010 |
133 pages |
| Authors:
Luke A Barger; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| Scattering matrix elements are calculated for the nonadiabatic inelastic collision . This calculation utilizes the effective potential energy surfaces for this collision generated by Garvin along with a correction to the asymptotic H2 potential. Wavepackets are propagated on these surfaces using a split-operator propagator. This propagation yields correlation functions between reactant and product Moller states which are used to calculate the scattering matrix elements with the channel packet method. These ... |
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| Optimal Finite-Thrust Trans-earth Injection (TEI) Maneuvers for a Low Lunar Orbit (LLO) Earth Return Mission |
Dec 2010 |
129 pages |
| Authors:
Omar J Wheatley; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Pseudospectral methods are used to efficiently solve complex, non-linear optimal control problems and can be used to develop rapid and robust control solutions in astrodynamics applications. With the renewed efforts in resuming future manned missions to the moon or near-earth asteroids, fuel optimal flight trajectories are desired in order to alleviate the need for overestimates in fuel carried onboard, which has a negative impact on the overall spacecraft design. This ... |
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| A Comparison of the Accuracy of Discrete Event and Discrete Time |
Dec 2010 |
11 pages |
| Authors:
Arnold Buss; Ahmed Al Rowaei; NAVAL POSTGRADUATE SCHOOL MONTEREY CA MODELING VIRTUAL ENVIRONMENTS AND SIMULATION (MOVES)
|
| Many combat and agent-based models use time-step as their simulation time advance mechanism. Since time discretization is known to affect the results when numerically solving differential equations, it stands to reason that it might likewise affect the results of such simulations. This paper demonstrates that is indeed the case. Using simple queueing models, we demonstrate that the size of the time step can have a substantial impact on estimated measures ... |
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| Instrumentation Analysis: An Automated Method for Producing Numeric Abstractions of Heap-Manipulating Programs |
29 NOV 2010 |
350 pages |
| Authors:
Stephen Magill; CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE
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| A number of questions regarding programs involving heap-based data structures can be phrased as questions about numeric properties of those structures. A data structure traversal might terminate if the length of some path is eventually zero or a function to remove n elements from a collection may only be safe if the collection has size at least n. In this thesis, we develop proof methods for reasoning about the connection ... |
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| Parameter Selection Methods in Inverse Problem Formulation |
03 Nov 2010 |
30 pages |
| Authors:
H T Banks; Ariel Cintron-Arias; Franz Kappel; NORTH CAROLINA STATE UNIV AT RALEIGH CENTER FOR RESEARCH IN SCIENTIFIC COMPUTATION
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| We discuss methods for a priori selection of parameters to be estimated in inverse problem formulations (such as Maximum Likelihood, Ordinary and Generalized Least Squares) for dynamical systems with numerous state variables and an even larger number of parameters. We illustrate the ideas with an in-host model for HIV dynamics which has been successfully validated with clinical data and used for prediction and a model for the reaction of the ... |
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Theoretical Mathematics
